Trichomoniasis is one of the most common sexually transmitted diseases of the urogenital tract. This infection has important medical and socio-economic significance because of the large numbers of people infected, often with a chronic form of the disease and relapses, and the caused damage to different organs and systems. World Health Organisation (WHO) data reveals that at the turn of the 20th and 21st centuries, almost half of all incidences of sexually transmitted infections were of trichomoniasis (Grodstein F. Relation of tubal infertility to a history of sexually transmitted diseases/F. Grodstein, M. B. Goldman, D. W. Cramer//Am. J. Epidemiol. —1993.—Vol. 137.—P. 577-584; Vilkki M., Pukkala E., Nieminen P. et al. Gynaecological infections as risk determinants of subsequent cervical neoplasia//Acta Oncol.-2000.—vol.—P. 71-75; Tikhomirov A. L. Urogenital trichomoniasis,/Tikhomirov A. L., Oleinik Ch. G.//Works of MGMSU-M., 2003, pp. 1-7). Urogenital trichomoniasis is usually transmitted during sexual contact between infected people or asymptomatic carriers of the disease. Non-sexual transmission can also occur. For example, mothers can infect their children during birth. It can also occur through the reuse of gloves during examinations. In addition, as the parasite can survive outside the body on infected items for a few hours, it can be transmitted through contact with infected diapers, bed-pans, toilet seats, and personal hygiene items (Isakov B. A., Zakharkiv Yu. F., Ermolenko D. K., et al. Diagnostics and treatment of urogenital trichomoniasis. Recommendations for physicians, St-Petersburg, Veliki Novgorod, 2006, p. 46).
A big significance in the epidemic process play people with weakly expressed symptoms and trichomonad carriers that facilitates the epidemiological spreading of the pathogen. Without treatment the protozoa survive in the body and cause numerous complications. Trichomoniasis has been diagnosed in 70 to 80-year old males who had their last sexual contacts 30 years ago.
Some medications, used for the treatment of trichomonas infection, lead to a relative reduction of symptoms. These drugs include acrichine, aminarson, dichloro-diphenyl-trichlorethane, and trichomycin. However, these substances are not very effective.
Women with urogenital diseases have been treated with phytotherapy that involved using extracts and tinctures obtained from onion, garlic, reddish, horseradish, pine and spruce needles, and jupiter.
Currently, metronidazole (synthesised in 1959) is widely used for the treatment of urogenital trichomoniasis. Widespread use was found for combination treatment methods, which included use of peroral and intravaginal drugs such as clion-D, gynalgin, tergynan, and metrogyl (Patent RU 2320319 “Vaginal suppositories”, 2006.11.07). However, at present, there is no reliable method of trichomoniasis treatment.
Lately, treatment of trichomoniasis has become more difficult because of the appearance of new strains that are multiresistant to therapeutic substances. It has been established that chronic urogenital trichomoniasis taking place in a form of mixed invasion is a reliable indicator of occurrence of drugs resistant strains of Trichomonas vaginalis. 
The existing treatment regimens often do not provide a significant effect as they do not take into account individual particularities of a patient. For example, the presence of concomitant diseases and changes in the immune system and the biological activity or resistance to therapeutic substances of the strain are not taken into consideration. Assessment of the sensitivity of T. vaginalis to antiprotozoal medications allows for a significant increase in the efficacy of treatment in patients with chronic urogenital trichomoniasis.
There are other pharmaceuticals such as mebendazole, butoconazole, and benzoisothiazolin (Vidal, Therapeutic substances in Russia, 6th edition, 2000).
There is a need for development of new therapeutic substances for using shorter as well as more complex methods for treatment of urogenital trichomoniasis based on studies of pharmacokinetics and sensitivity of various strains of T. vaginalis to the same dose of used therapeutic substance (Narcisi E. M. In vitro effect of tinidazole and furazolidone on metronidazole-resistant Trichomonas vaginalis/E. M. Narcisi, W. E. Secor//Antimicrob. Agents Chemother.—1996.—Vol. 40. pp. 1121-1125; Zakharkiv Yu. F., Dependence of efficacy of etiotropic therapy of patients with trichomoniasis on sensitivity of strains of a pathogen to antiprotozoic drugs; Zakharkiv Yu. F., Poznyak A. L., Sidorchuk S. N., Gudkov P. B. Materials of the Russian Scientific Conference “Key issues in fighting infection”, St-Petersburg, Military Medical Academy, 2004, pp. 192-193). Traditional anti-protozoan therapy leads to a significant improvement in the patient's condition and etiological recovery. However, clinical recovery does not occur in 64% of patients due to the development of post-trichomonal urethritis (PTU). In these cases, patients complain about unpleasant sensations during urination and periodic mucous-purulent discharge from the urethra (Vilkki M., Pukkala E., Nieminen P. et al. Gynecological infections as risk determinants of subsequent cervical neoplasia//Acta Oncol.—2000.—vol.—pp. 71-75). A thorough laboratory examination for the presence of trichomoniasis produces a negative result and additional anti-protozoan therapy is not successful. From clinical point of view, post-trichomonad urethritis has an undulating or monotonous character. Patients become irritable, have sleeping disorders, and can develop sexual dysfunction. The most frequent cause of PTU is the presence of other sexually transmitted pathogens. Urogenital trichomonas provides a depot for the survival of gonococci, fungi, chlamydiae, mycoplasma, and viruses (Thomason J. L. Trichomonas vaginalis/J. L. Thomason, S. M. Gelbert//Obstetrics and Gynaecology.—1989.—Vol. 74. pp. 536-541) since enzymes of protozoa cannot always destroy phagocytised by them microorganisms. Subsequently, these pathogens can support the inflammatory process for extended period of time. It has been established that trichomonas prevents the detection of chlamydia in cell culture. Clinically, inflammation due to mycoplasma and chlamydia occurs with relapses, often with damage to the accessory sexual glands. Development of PTU is facilitated not only by microflora that accompanies urogenital trichomoniasis, but also by the formation of L-form microorganisms and the reduction of immunobiological resistance in the host body. This also includes local immunity in the organs of the urinary system.
Recently, medical practitioners have found that treating urogenital trichomoniasis with metronidazole is ineffective. These failures can be related to low content of zinc in the blood (Debbia E. A. In vitro activity of metronidazole alone and in combination with clotrimazole against clinical isolates of Trichomonas vaginalis./E. A. Debbia, U. Campora, S. Massaro et al.//J. Chemother.—1996. Vol. 8, N2.—P. 96-101; Taru Meri I. T. Resistance of Trichomonas vaginalis to Metronidazole: Report of the First Three Cases from Finland and Optimization of In Vitro Susceptibility Testing under Various Oxygen Concentrations/I. T. Taru Meri, Sakari Jokiranta, I. Lauri Suhonen et al.//Journal of Clinical Microbiology.—2000.—Vol. 38.—No2. pp. 763-767), low absorption of the drug (Du Bouchet L. Multicenter comparison of clotrimazole vaginal tablets, oral metronidazole, and vaginal suppositories containing sulfanilamide, aminacrine hydrochloride, and allantoin in the treatment of symptomatic trichomoniasis/L. Du Bouchet, M. R. Spence, M. F. Rein et al.//Sex. Transm. Dis.—1997.—N3.—P. 156-60 Honigberg B. M. Structure of Trichomonas vaginalis Donne/B. M. Honigberg, V. M. King//J. Parasitol.—1964.—Vol. 50.—P. 345-364; Land K. M., Delggadillo-Corea M. G., Tachezy G. et al/. Targeted gene replacement of ferredoxin gene in T. vaginalis does resistance//Mol. Microbiol.—2004.—vol. 51.—P.115-120), and inefficient delivery of the drug to the vagina or inactivation of the drug by the vaginal flora (Borchardt K. A. A comparison of the sensitivity of the In Pouch TV, Diamond's and Trichosel media for detection of Trichomonas vaginalis./Borchardt K. A., Zhang M. Z., et al///J. Genitourin Med.—1997.—Vol. 4.—P. 297-298).
Other researchers suggest that the ineffectiveness of metronidazole could be due to previous multiple unsuccessful treatment attempts (Narcisi E.M. In vitro effect of tinidazole and furazolidone on metronidazole-resistant Trichomonas vaginalis/E. M. Narcisi, W. E. Secor//Antimicrob. Agents Chemother.—1996.—Vol. 40.—P. 1121-1125).
Resolving the issue of metronidazole-resistant organisms can be achieved by a number of ways. These include increasing the dose of metronidazole; use of a combination of various anti-trichomonas therapeutic substances, and using these substances in conjunction with nonspecific therapy (Narcisi E.M. In vitro effect of tinidazole and furazolidone on metronidazole-resistant Trichomonas vaginalis/E.M. Narcisi, W.E. Secor//Antimicrob. Agents Chemother.—1996.—Vol. 40.—P. 1121-1125).
Currently, urogenital trichomoniasis is treated with metronidazole and other nitroimidazoles, such as tinidazole, ornidazole, secnidazol, nimorazole, and carnidazole.
Metronidazole, which is included in individual and combined treatments of trichomoniasis, was selected as the comparator drug for the study described in this document.